This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Vitamin B12 deficiency is a significant public health problem. Recent studies have shown a strong association between plasma B12 concentrations and dairy, egg, meat, and seafood intake. These data also suggested that there are differences in the relative bioavailability of B12 from these different sources. The aim of the study is to determine vitamin B12 bioavailability from egg and compare it to standard supplement.